Automatic gram-staining with the microstainer II.

A comparison was made between the Microstainer II, an automatic staining machine, and the traditional, manual gram-staining method using clinical material and known organisms in a double blind study. Gram-reactions were in agreement with 98.4% of the organisms. The machine-stained microorganisms were generally found to be of the same or better quality than manually-stained organisms. Transfer of bacteria from slide to slide or smear to smear was not a significant problem. The Microstainer II would appear to be a useful addition to the large volume bacteriology laboratory.